Ever woken up to a fridge that seems suspiciously empty? It could be that people are sneaking into your house, eating your food and perhaps using your toothbrush. Or possibly you have been getting up in the middle of the night and eating while you are asleep. Welcome to Nocturnal Sleep-Related Eating Disorder.

Ever eaten a buttered cigarette? If you have Nocturnal Sleep-Related Eating Disorder or NSRED, you might have. It's associated with other sleep disorders, like restless leg syndrome or sleepwalking. Certain people, instead of walking in their sleep, are wired to eat in their sleep. The disorder most often starts up during a person's thirties, with some precipitating event. Often the event is sickness or extreme stress, but sometimes it's started when you take certain drugs, or withdraw from them — notably nicotine. As the disorder kicks in, it's not unusual for people to have flashes of memory about what they did in the night. They generally remember the more complicated maneuvers, which need more of a conscious mind and make an impression. Eventually their minds adjust to the trips to the kitchen, and they become amnesiac to all but the most extreme behaviors. One man, finding no food at all in the kitchen, got on a motorcycle and drove to a supermarket, but only remembered flashes from his trip in the morning.

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The syndrome might seem like an excuse for people looking to break their diet, but few people would consider eating the way sleep eaters do. NSRED sufferers eat unthawed frozen food. They munch on food made for their pets. They eat salt sandwiches and crunch on uncooked pasta. And yes, some do eat cigarettes. (Others smoke them while eating. One man realized his sleep eating problem hadn't cleared up when the ash from his cigarette burned him and woke him up in the middle of eating.) When patients prepare more elaborate meals, they can cut or burn themselves badly while preparing the food. Even basic foods pose a problem. Peanut butter seems to be a favorite food of sleep eaters, but during sleep the instinct to swallow doesn't always kick in, and they choke on it. (This may be one reason for the infamous arachibutyrophobia - the fear of getting peanut butter stuck to the roof of your mouth.)

Unsurprisingly, even those who don't choke on peanut butter or burn their hands on the stove come in to be studied at sleep clinics. As the disorder escalates, people can be up and eating four times a night. Not everyone gains weight, but pretty much everyone feels sick in the morning. (I suppose there are only so many times you can throw up a cigarette before seeking medical treatment.) Sleep clinics have studied the neurology of NSRED. Some patients start eating during an early of sleep generally characterized by the first decrease of heart rate and body temperature. More often the eating occurs during delta sleep. It's a deep sleep, just before REM sleep starts, and requires a particular frequency of brain waves, called delta waves. Sleep walkers, alcoholics, severe depressives, and people with Parkinson's disease often have disrupted delta sleep. Delta-like waves have also shown up in epileptics while they are having seizures. Almost all sleep disorders start in this stage of sleep, and sleep eating doesn't appear to be any different.

This disorder was first reported in 1955, at which point doctors were stumped by how to treat a behavior that the patient didn't know they were displaying and a mental state that they couldn't control. Few sleep-eaters have found talk therapy effective. As medications arose, and more was understood about the disorder, medications came up that would get NSRED under control. Patients who have had NSRED induced by other medication often respond to temazepam, an insomnia, anti-anxiety, and anti-convulsant treatment. Others generally do well with other anticonvulsants, and with some opiates. Get control of the neurochemisty, and people can get control of the disorder.

There are still questions. Why do these patients feel the need to use their sleep disorder to eat, rather than any other activity? And what makes them choose particular foods, especially ones that might make them choke, when many have demonstrated that they're capable of cooking a full meal? So far, no one has any answers. Hopefully, some day we'll be able to re-wire our brains to do useful things while we sleep. Until then, we just have to stock the fridge with something good.